I. Field
The present disclosure relates generally to electronics, and more specifically to a time-to-digital converter (TDC).
II. Background
A TDC is a digital circuit that receives an input signal and a reference signal, detects the phase difference between the two signals, and provides a digital value of the detected phase difference. The phase difference between the two signals may be given by the time difference between the leading edge of the input signal and the leading edge of the reference signal. The TDC typically includes a set of inverters coupled in series and used to determine the phase difference between the two signals. The TDC digitizes this phase difference and provides the digitized phase difference. The resolution of the TDC, which is the quantization step size for the digitized phase difference, is typically determined by the delay of one inverter in the set of inverters.
The TDC may be used in a digital phase locked loop (DPLL) or some other circuit. It may be desirable to obtain fine resolution for the TDC in order to improve the performance of the DPLL or some other circuit in which the TDC is used.